Aquaculture is the fastest growing food production sector globally and investing in research that has the potential to improve farmed species’ resilience to climate change will be critical for industry growth. Stress priming, also called stress hardening or conditioning, can induce short or long-term stress ‘memory’ that can enhance ability to cope with environmental challenges. Priming has been well-studied in crop production and has growing recognition in aquaculture as the environments that aquacultured organisms are outplanted into are becoming increasingly unpredictable and extreme. One step in the aquaculture process that is particularly vulnerable is when oysters are shipped from a hatchery, where they are kept in a relatively homogeneous subtidal environment, to a grow-out farm, where they are exposed to air for several hours each day (low tide).
We exposed year-old hatchery-produced Crassostrea gigas that were ready for transport to a grow-out farm to a 6-hour air exposure (priming event). After 1, 2, or 3 days of recovery, both control and primed oysters were subjected to a two-hour low tide. We found that primed oysters maintain a stable rate before and after low tide while the control oysters had a significant increase after the low tide (See Figure 1). This elevated ‘oxygen debt’ in control oysters indicates a heightened metabolic cost of restoring cellular homeostasis. We hypothesize that the primed individuals had previously upregulated antioxidant defenses during recovery from priming, which reduced the amount of oxidative stress experienced during the low tide.
The results of our study suggest that air priming may have a positive influence on the oysters’ ability to smoothly transition to the intertidal zone by reducing the amount of oxygen debt they ‘owe’ after a low tide.